用固体核磁方法研究MCM-22分子筛中的Al状态  

CHARACTERIZATION OF Al SPECIES IN MCM-22 ZEOLITE BY SOLID STATE NMR

作　　者：罗晴[1] 程谟杰[2] 邓风[1] 

机构地区：[1]中国科学院武汉物理与数学研究所波谱与原子分子物理国家重点实验室,武汉430071 [2]中国科学院大连化学物理研究所催化基础国家重点实验室,大连116023

出　　处：《波谱学杂志》2001年第2期143-148,共6页Chinese Journal of Magnetic Resonance

基　　金：国家自然科学基金!资助项目 (批准号 :2 970 30 0 9;2 99730 58)

摘　　要：用固体NMR技术研究了新型分子筛MCM 2 2在不同水合状态下的2 7Al谱和1 H谱 .并用新的1 H/2 7Al双共振方法TRAPDOR对MCM 2 2分子筛的各种铝状态进行了研究 ,得到了样品脱水后B酸位 (Bronsted)、L酸位 (Lewis)以及非骨架Al(OH)的四极耦合常数 .MCM-22 is a new molecular sieve which is expected to be widely used in chemical industry. In this paper we study the {}+{27}Al species of different acid sites in the MCM-22. {}+{27}Al spectra of samples rehydrated in differently extent have been acquired. It is difficult to get high resolution {}+{27}Al spectrum of the dehydration powder sample directly because of the existence of strong quadrupole interaction which comes from asymmetric local chemical environment. In order to overcome the strong quadrupole interaction of {}+{27}Al, the double resonance NMR method {}+1H/{}+{27}Al TRAPDOR is used in this study. Quadrupole coupling constants (QCC) for aluminum species are abtained. By calculation of the second order quandrupole line width of these aluminum species , it can be concluded that 4-, 3-coordinate framework aluminum and extra-framework alumium are all the source of the “NMR invisible aluminum”. ;

关 键 词：TRAPDOR 酸位 MCM-22分子筛 铝状态 固体核磁共振 四极耦合常数 MAS 

分 类 号：TQ424.25[化学工程] O641.13[理学—物理化学]